The present invention relates to a water treatment apparatus.
A water treatment apparatus is provided for a piping configured to supply water, cold water, warm water and the like to a variety of buildings requiring water such as a factory, an apartment, a swimming pool and a bathhouse, and is used for preventing corrosion and rust of the piping and also for preventing generation and accumulation of bacteria or scale in the piping.
In order to prevent and remove the scale, a method of applying an electric field to the piping, i.e., a method of using an electrostatic field is used.
FIG. 1 depicts an example of the water treatment apparatus of the related art.
A water treatment apparatus using an electrostatic field (hereinafter, simply referred to as ‘electrostatic field water treatment apparatus’) serves as a dielectric having anode (+) and cathode (−) surfaces, like an electrostatic capacitive capacitor. For example, when a cylindrical pipe or a flat plate-type pipe is applied with direct current or pulse direct current of anode (+) and cathode (−), an electrostatic field is formed between the anode (+) and the cathode (−).
When water exists between the anode (+) electrode and the cathode (−) electrode, an electric field is filled across the water. In order to treat much water over a wide area, a flat plate-type water treatment apparatus having an anode (+) electrode and a cathode (−) electrode may be provided.
In the cylindrical structure, the capacitance can be expressed as follows.
                    C        =                              Q            V                    =                                    2              ⁢                              πɛ                0                            ⁢              l                                      ln              ⁡                              (                                  b                  /                  a                                )                                                                        [                  equation          ⁢                                          ⁢          1                ]            
herein,                C: capacitance, Q: charge quantity, V: voltage,        L: length of cylinder,        ε0: dielectric constant of vacuum (8.854×10−12 F/m), ln: Napierian logarithm,        a: distance from center of cylinder to outer diameter of electrode,        b: distance from center of cylinder to inner diameter of pipe.        
In the flat plate-type structure, the capacitance can be expressed as follows.
                    C        =                              Q            V                    =                                                    ɛ                0                            ⁢              A                        d                                              [                  equation          ⁢                                          ⁢          2                ]            
herein,                A: sectional area (m2) of flat plate, d: distance (m) of flat plate.        
A principle of the electrostatic field water treatment apparatus is to apply a very high direct current voltage or pulse voltage (maximum 1,000V or higher) to the anode (+) electrode and the cathode (−) electrode of the pipe structure or flat plate-type structure so as to influence particles, bacteria and the like in the water. In this case, a magnitude of current is very small (0.01 A or less) and does not influence performance of the apparatus.
The cell membrane of the bacteria in the water has a phospholipid bilayer and consists of hydrophilic head parts and hydrophobic tail parts. A material to be transferred into the cell moves thorough the protein in the cell membrane. The surface tension of phospholipid is appropriately balanced, so that the structure of the cell membrane is maintained.
When the bacteria exist in the electrostatic field water treatment apparatus having a very high electrostatic field, the surface tension characteristic of the bacteria moving in the water stream is changed by the high electrostatic field, so that the balance of the cell membrane is upset. As a result, the positions and structures of the hydrophilic head parts and hydrophobic tail parts of phospholipid are newly modified, so that parts to be aligned and parts to be destroyed are generated. During the process, the cell membrane is formed with a hole, so that foreign matters such as water and ions are introduced into the cell. Thereby, the bacteria swell and die out.
Also, the electrostatic field water treatment apparatus having a very high electrostatic field is configured to supply electrons to the water flowing between (+) and (−) electrodes, to electrically neutralize cations (Ca++, Mg++, Fe++) of the scale component, and to apply a repulsive force. Thereby, it is possible not only to generate the scale component but also to separate crystalline compound of the scale attached to the existing discharge piping. Also, the electrons to be included in the water increase, so that it is possible to suppress the corrosion, which is to be caused due to electron elution of metal. The electrostatic field water treatment apparatus is based on the principle of the capacitor using the high dielectric constant (ε≈80) of water.
For example, in the electrostatic field water treatment apparatus, the dielectric electrode having anode (+) and cathode (−) surfaces, like the electrostatic capacitive capacitor, is configured as follows.
The electrodes can be classified into a high potential electrode and a low potential electrode. In this case, the electrode of which potential is 0V is connected to an earth ground, and the earth ground becomes a cathode (−) electrode. The high potential electrode (about +1,000V or −1,000V) becomes an anode (+) electrode.
A large current flows through the water between the anode (+) and cathode (−) surfaces. Therefore, in order to suppress the current flow at the maximum and to configure an electrode having the same principle as the electrostatic capacitive capacitor, the high potential anode (+) electrode is connected to a conductor made of copper, aluminum, titanium, iron or the like, and the conductor is sealed with close adhesion by an insulation film 20 made of rubber, ceramic, Teflon, polyethylene, polypropylene, polyurethane, PVC or the like and is stably insulated up to the service lift (five years or longer) depending on the high voltage to be applied. The cathode (−) electrode consists of the conductor, and is connected to a water coupling pipe main body and the earth ground.
Making an additional remark, in the electrostatic field water treatment apparatus, as shown in FIG. 1, an electrode rod 10 is mounted in a cylindrical pipe 30 through which the water flows. The cylindrical pipe 30 is applied with the (−) voltage and the internal electrode rod 10 disposed in the cylindrical pipe 30 is applied with the (+) voltage. Here, it is important how much the internal electrode rod 10 is stably insulated.
In the electrostatic field water treatment apparatus of the related art, the insulation film 20 is used so as to insulate the internal electrode rod 10. In this case, it is difficult to perform an assembling operation. Also, when the insulation film 20 is formed with a pinhole, the dielectric breakdown may be caused. Therefore, careful attention should be paid to the protection of the insulation film 20 of the internal electrode rod 10.
In order to insulate the internal electrode rod 10, Teflon may be used as the insulation film 20. However, Teflon is difficult to be processed and is high in price. The service life of the electrostatic field water treatment apparatus using Teflon is shortened at the high voltage, so that a replacement time period of the electrode rod is short. Therefore, when Teflon is used, the managing cost may increase.
In order to insulate the internal electrode rod 10, ceramic may be used as the insulation film 20. However, the ceramic is difficult to be processed and is expensive. The service life of the ceramic is very long. However, the ceramic is fragile and is difficult to be handled.
Also, in the electrostatic field water treatment apparatus of the related art as shown in FIG. 1, a water inlet direction and a water outlet direction are perpendicular to each other, so that resistance against the water flow is caused in the electrostatic field water treatment apparatus. Also, the electrostatic field water treatment apparatus of the related art is difficult to be mounted to the existing pipe equipment.